Tandem hydraulic press



Dec. 24, 1963 A. A. ZANDEL 3,115,089

TANDEM HYDRAULIC PRESS Filed Sept. 24, 1962 l 54 l 503 I I r 1 I 34* I l 3o" I /4 I l l 5 2g 44 3/ 68 1 42 52 l 50 l 62 I 64 5a I so a l l I I 46 42 V I 4 26 Z I .22 g! -v 25 a4 90 7a :65 I 22 A 74 7a P 86' I ea ea 87 .04 as 72 INVENTOR.

ADAM A. ZANDEL ATTOR/Vf) United States Patent 3,115,989 TANDEM HYDRAULIC PRESS Adam A. Zandel, Swarthmore, Pa., assignor to Baldwin- Lima-Hamilton Corporation, Philadelphia, Pa., a corporation of Pennsylvania Filed Sept. 24, 1962, Ser. No. 225,620 3 Claims. (Cl. t)214) In general, this invention relates to a new and improved hydraulic press and, more particularly, to a large capacity hydraulic press in which a single platen is driven by two cylinders connected in tandem relation.

in building large hydraulic presses, the capacity of the press is limited by the size of the driving cylinder that can be economically forged, cast or otherwise manufactured in one piece and the size suitable for shipping by rail. In this regard, if a 20,000 ton press were built and 2,000 pounds per square inch hydraulic pressure were available for use, a conventional single press cylinder would have to be 160 inches in diameter. This is almost an impossible cylinder to manufacture and ship by rail.

Multiple cylinders for combined single conventional action are too expensive to manufacture because of the required support structures for them. Additionally, a single press cylinder produces unfavorable horizontal force vectors when the press load is oif center. The horizontal force vectors create bending moments on the tension bars between the platens of the press.

In a single cylinder press, it is diflicult to operate at reduced capacity. The pressure regulation facilities must be intricate in order to control the force of the single cylinder.

Therefore, it is the general object of this invention to avoid and overcome the foregoing and other difliculties of prior art practices by the provision of a new and improved tandem hydraulic press.

Another object of this invention is to provide a new and better hydraulic press capable of reducing horizontal force vectors created by off center load positions.

A further object of this invention is to provide a better hydraulic press which can be utilized at reduced capacity without the necessity for pressure regulation facilities.

Another object of this invention is to provide a large capacity hydraulic press which can be designed to occupy less floor space in an installation.

Other objects will appear hereinafter.

For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

In the drawing, there is shown a cross sectional view of a hydraulic press built in accordance with the principles of the present invention. The tandem hydraulic press shown in the drawing is generally designated by the numeral 10.

The press 10 includes a lower stationary platen 12 and an upper vertically reciprocal platen 14. The lower platen 12 rests on the ground 16. An upper cylinder 18 and its associated piston 20 directly drive the upper platen 14. Hydraulic fluid is adapted to be received within the cylinder 18 through a port 19. Since the piston 20 is directly coupled to the upper platen 14, pressure within the cylinder 18 will force the platen 14 downwardly.

A lower cylinder 22 and its associated piston 24 are additionally operative to force upper platen 14- downwardly. Hydraulic fluid is received in cylinder 22 through a suitable port 23 located below the piston 24. The piston 24 is directly coupled to the lower platen 112. The manner in which lower cylinder 22 and piston 24 drive upper platen 1-4 will be discussed below.

The upper cylinder 18 has at least two tension bars 3,115,089 Patented Dec. 24, 1963 29 and 31 fixedly connected thereto by flanged portions 30 and 32. The upper cylinder tension bars 29 and 31 are also fixedly connected to the lower platen 12 by flanged end portions 38 and 4% respectively. The tension bars 29 and 31 pass freely through guide openings 34 and 36 provided in upper platen 14. Thus, the upper cylinder 18 remains fixedly spaced from the lower platen 12 during movement of the upper platen 14. Hydraulic pressure in the cylinder 18 will force piston 20 downwardly and thereby drive upper platen 14.

The lower platen 12 has a centrally located housing 26 placed within an indentation 28 in the ground 16 so as to provide stability for the press =10.

The lower cylinder 22 has tension bars 42 and 44 connected thereto by flanges 46 and 48 respectively. The tension bars 42 and 44 are also fixedly connected to the upper platen I14 by flanges 54 and '56. The tension bars 42 and 44 pass freely through guide slots 50 and 52 in lower platen '12.

Therefore, if hydraulic pressure is introduced into lower cylinder 22, the piston 24 will remain stationary while the cylinder 22 moves downwardly. Downward movement of the cylinder 22 will be transmitted directly through tension bars 42 and 44 to the upper platen 14 which will also move downwardly. There is no lost motion between the lower cylinder 22 and the upper platen 14.

Thus, it can be seen that pressure introduced into either or both of cylinders 18 and 22 will induce downward movement of platen 14-.

To raise upper platen 14 after a press operation, lift cylinders 58 and 60 are provided. Hydraulic fluid may enter lift cylinders 58 and 60 through ports 59 and 61. The size of lift cylinders 58 and 6d can be considerably less than the size of cylinders 13 and 22 as only the weight of upper platen 14 need be raised. Cylinders 58 and 69 are provided with pistons 62 and 64 respectively. The pistons 62 and 64 are connected to the upper platen 14 by piston rods 66 and 68 respectively.

A sample hydraulic system for operating the press 10 is discussed below, but it should be understood that any hydraulic system capable of performing the operations of the tandem press 10 would be suitable.

The hydraulic system for the tandem press 10 is operatively powered by a pump 70 receiving hydraulic fluid from a tank '72. The pump 70 feeds hydraulic fluid under pressure through a conduit 74 to a three-way valve 76. The valves shown in the drawing are in position to force the upper platen 14 in a downward direction.

The three-way valve 76 is shown connected to a conduit 78 for this operation. The three-way valve '76 is also capable of supplying fluid to a conduit 80 for a reason to be discussed below.

The conduit 78 feeds a second three-way valve 82 in position to supply fluid to two conduits 84 and 8 8. A third conduit 86 is not supplied fluid from conduit 78 but is connected directly back to the tank 72.

The conduits 84 and 88 supply fluid to cylinders 18 and 22 respectively. Conduits 84 and 88 have in line valves and 87 to stop the flow of hydraulic fluid to any given cylinder. By closing one of the valves 85 and 87, it is possible to utilize only a single cylinder during the pressing operation.

In this manner, different forces are able to be utilized by the press 10 without the necessity of pressure regulating equipment. Llf the cylinders 18 and 22 have different capacities, three different pressure ranges are possible without the above-mentioned pressure regulating equipment. These three ranges are the pressure in cylinder 13 alone, or cylinder 22 alone, or the combination of cylinders 18 and 22.

After the pressing operation is completed, valve 76 is turned 90 degrees and valve 82 is turned 180 degrees. In this position, the hydraulic fluid in cylinders 18 and 22 will flow back through conduits 84 and 88 and into conduit 86 to the tank 72. The pump 70 will then supply 'a distribution valve 89 with hydraulic fluid through conduit 80. The distribution valve 89 will supply the hydraulic fluid through conduits 90 and 92 to cylinders 58 and 60. These cylinders will be operative through their respective pistons and piston rods to raise upper platen 14 thereby forcing the remaining fluid out of cylinders 18 and 2 2. When the raising operation is completed, distribution valve 89 is actuated to cut off the flow through conduit 80 and connect conduits 90 and 92 to a conduit 94. This last-mentioned conduit is connected back to the tank 72 so that when the press is again moved downwardly, hydraulic fluid will flow from the cylinders 58 and 60 back into the tank 72.

Thus, it can be seen that the objects of the present invention have been accomplished by the provision of a new and better hydraulic press operative through a tandem cylinder arrangement. The tandem arrangement of the present invention would allow two 113 inch diameter cylinders to create the same amount of power that is created by a single 160 inch diameter cylinder in a single cylinder press. Thus, each of the cylinders 18 and 22 if supplied with 2,000 p.s.i. hydraulic pressure would create a force of 10,000 tons. The tandem press would then have a total capability of 20,000 tons.

If the cylinders 18 and 22 were of different diameters, different values of force could be utilized in the press without the necessity of intricate pressure regulation facilities. When only one cylinder is utilized, increased speed of operation occurs.

Because of the tandem arrangement of the cylinders, the support of the platen through its tension bars is operative to reduce horizontal force vectors created by off center load positions and therefore, bending moments on the tension bars are reduced.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

1 claim:

'1. A tandem hydraulic press comprising a stationary bedplate, a stationary crosshead mounted above and spaced from said bedplate, guide rods fixedly securing said crosshead to said bedplate, a reciprocal platen mounted between said crosshead and said bedplate and having said guide rods passing therethrough for guiding the reciprocal movement of said platen, said crosshead having a ventioal cylinder therein, said crosshead cylinder having a closed upper end and an open lower end, said reciprocal platen having a piston integral therewith extending upwardly into said crosshead cylinder, said platen piston being in slidable fluid-sealing relation with said crosshead cylinder, a bedplate piston integral with and extending downwardly from the bottom surface of said bedplate, a reciprocal cylinder mounted below said bedplate in slidable fluid-sealing arnangement with respect to said bedplate piston, said platen piston having a piston head at its upper end, said bedplate piston having a piston head at its lower end, said pistons being circular in cross section, said piston heads having convex exposed worked surface areas, said crosshead cylinder closed end having a concave work surface, said reciprocal cylinder having a lower closed end, said reciprocal cylinder lower closed end having a concave work surface, motive fluid supply means for introducing motive fluid into said crosshead cylinder at the center of said concave work surface, said motive fluid supply means additionally being operative to introduce motive fluid into said reciprocal cylinder at the center of said reciprocal cylinder concave work surface, vertical reciprocal joining rods, said joining rods passing through said bedplate and being fixed at opposite ends thereof to said platen and said reciprocal cylinder, at least two vertically aligned lift cylinders formed on opposite ends of said bedplate, lift piston rods for each of said lift cylinders, said lift piston rods being vertically reciprocal and having their lower ends within said lift cylinders and their upper ends fixed to said reciprocal platen, said motive fluid supply means being operative to supply motive fluid to the lowermost ends of said lift cylinders.

2. The tandem hydraulic press of claim 1 wherein said bedplate is adapted to be mounted on the surface above an open pit, said bedplate piston and reciprocal cylinder extending downwardly into said pit, said bedplate having a downwardly extending integral hollow housing, said bedplate housing having its outer side walls conforming to the surface of said open pit, said bedplate hollow housing having a central opening therein for receiving said reciprocal cylinder in its lowermost position.

3. The tandem hydraulic press of claim 1 wherein said motive fluid supply means includes a pump, valve means, and a reservoir, said pump being connected to said reservoir to pump fluid from said reservoir, said valve means having a first position connecting said pump to said crosshead cylinder and said reciprocal cylinder, said valve means in said first position additionally preventing the flow of fluid from said pump to the bottom of said lift cylinders, said valve means in said first position connecting the lowermost ends of said lift cylinders to said reservoir, said valve means having a second position, said valve means second position connecting said pump to the bottom of said lift cylinders and disconnecting the bottom of said lift cylinders from said reservoir, said valve means second position additionally preventing the flow of motive fiuid from said pump to said crosshead and reciprocal cylinder, said valve means second position further connecting the center of said crosshead cylinder concave work surface and the center of said reciprocal cylinder concave work surface for fluid communication with said reservoir. 3

References Cited in the file of this patent UNITED STATES PATENTS 760,592 Westmark May 24, 1904 1,407,146 Gil ling Feb. 21, 1922 1,721,421 Updegraif July 16, 1929 2,197,441 Perony Apr. 16, 1940 FOREIGN PATENTS 522,065 Great Britain June 7, 1940 541,227 France Apr. 29, 1922 895,830 Germany Nov. 5, 1953 

1. A TANDEM HYDRAULIC PRESS COMPRISING A STATIONARY BEDPLATE, A STATIONARY CROSSHEAD MOUNTED ABOVE AND SPACED FROM SAID BEDPLATE, GUIDE RODS FIXEDLY SECURING SAID CROSSHEAD TO SAID BEDPLATE, A RECIPROCAL PLATEN MOUNTED BETWEEN SAID CROSSHEAD AND SAID BEDPLATE AND HAVING SAID GUIDE RODS PASSING THERETHROUGH FOR GUIDING THE RECIPROCAL MOVEMENT OF SAID PLATEN, SAID CROSSHEAD HAVING A VERTICAL CYLINDER THEREIN, SAID CROSSHEAD CYLINDER HAVING A CLOSED UPPER END AND AN OPEN LOWER END, SAID RECIPROCAL PLATEN HAVING A PISTON INTEGRAL THEREWITH EXTENDING UPWARDLY INTO SAID CROSSHEAD CYLINDER, SAID PLATEN PISTON BEING IN SLIDABLE FLUID-SEALING RELATION WITH SAID CROSSHEAD CYLINDER, A BEDPLATE PISTON INTEGRAL WITH AND EXTENDING DOWNWARDLY FROM THE BOTTOM SURFACE OF SAID BEDPLATE, A RECIPROCAL CYLINDER MOUNTED BELOW SAID BEDPLATE IN SLIDABLE FLUID-SEALING ARRANGEMENT WITH RESPECT TO SAID BEDPLATE PISTON, SAID PLATEN PISTON HAVING A PISTON HEAD AT ITS UPPER END, SAID BEDPLATE PISTON HAVING A PISTON HEAD AT ITS LOWER END, SAID PISTONS BEING CIRCULAR IN CROSS SECTION, SAID PISTON HEADS HAVING CONVEX EXPOSED WORKED SURFACE AREAS, SAID CROSSHEAD CYLINDER CLOSED END HAVING A CONCAVE WORK SURFACE, SAID RE- 